rndering

[coffee]

i want to render a concrete extension . what is the best mix ratio and
what is the best way to scratch the bottom coat with. rendered part of
other extension 3 years ago and the render has blown in parts allready.
what did i do wrong.

 

[beermonsta]

Seal it first with PVA glue and water mix. Sounds like the wall has soaked up all the moisture in the render and caused it to blow. Applying water to the wall first can also help